U.S. patent number 6,688,444 [Application Number 10/243,186] was granted by the patent office on 2004-02-10 for power switching apparatus.
This patent grant is currently assigned to Showa Corporation. Invention is credited to Eiichi Terada.
United States Patent |
6,688,444 |
Terada |
February 10, 2004 |
Power switching apparatus
Abstract
In a power switching apparatus which moves cages respectively
corresponding to left and right two driven members in an axial
direction, end surfaces of the respective cages are brought into
frictional contact with the driven members so as to rotate together
therewith, and a wedge connection occurs in a circumferential
connection surface of a drive member to each of circumferential
connection surfaces in both of the driven members according to an
interposition of rolling elements, at a time of switching a power
transmitting state from the drive member to both of the driven
members. A spacer which is coaxially arranged with the driven
members is provided between both of the driven members, and both of
the cages are coaxially supported by an outer periphery of the
spacer.
Inventors: |
Terada; Eiichi (Tochigi,
JP) |
Assignee: |
Showa Corporation
(JP)
|
Family
ID: |
28035823 |
Appl.
No.: |
10/243,186 |
Filed: |
September 13, 2002 |
Foreign Application Priority Data
|
|
|
|
|
Mar 25, 2002 [JP] |
|
|
2002-084304 |
|
Current U.S.
Class: |
192/48.2; 192/50;
74/650 |
Current CPC
Class: |
F16D
27/108 (20130101); F16H 48/16 (20130101); B60K
23/06 (20130101); B60K 23/08 (20130101); F16H
48/12 (20130101); F16H 2048/426 (20130101); Y10T
74/19005 (20150115) |
Current International
Class: |
F16D
27/10 (20060101); F16D 41/00 (20060101); F16D
41/067 (20060101); F16D 27/108 (20060101); B60K
23/06 (20060101); B60K 23/08 (20060101); B60K
23/00 (20060101); F16H 048/16 (); B60K
023/04 () |
Field of
Search: |
;192/35,38,44,48.2,49,50,84.8 ;74/650 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2000-326748 |
|
Nov 2000 |
|
JP |
|
2001-80385 |
|
Mar 2001 |
|
JP |
|
Primary Examiner: Lorence; Richard M.
Attorney, Agent or Firm: Orum & Roth
Claims
What is claimed is:
1. A power switching apparatus for switching a power transmitting
state from a drive member to two right and left driven members,
comprising: a circumferential connection surface provided in a
drive member, and circumferential connection surfaces provided in
both of the driven members, the circumferential connection surface
of the drive member and the circumferential connection surfaces of
the driven members being coaxially arranged inside and outside; an
annular space which forms a wedge-like gap in a peripheral
direction between the circumferential connection surface of the
drive member and the circumferential connection surfaces of both of
the driven members in a repeated manner; cages respectively
corresponding to both of the driven members, the cages being
received in the annular space; a plurality of rolling elements
which are held at a plurality of positions in a peripheral
direction of each of the cages; an energizing member which brings
each of the rolling elements into contact with the circumferential
connection surfaces in the drive means and one of the driven
members, and energizes each of the rolling elements in a direction
in which the rolling elements are not in contact with the
circumferential connection surfaces in the drive member and another
of the driven members; and a switching means which moves each of
the cages in an axial direction, brings an end surface of each of
the cages into frictional contact with the drive member and another
of the driven member so as to rotate together therewith, and wedge
connects the circumferential connection surface of the drive member
and each of the circumferential connection surfaces in both of the
driven members according to an interposition of the rolling
elements, wherein a spacer which is coaxially arranged with the
driven members is provided between both of the driven members, and
both of the cages are supported by an outer periphery of the
spacer.
2. A power switching apparatus as claimed in claim 1, wherein each
of both end portions of the spacer and each of the end portions in
both of the driven members are coaxially fitted to each other.
3. A power switching apparatus according to claim 2, wherein a
step-like outer diameter portion is provided in a protruding manner
in each of both side end surfaces of the spacer, and the step-like
outer diameter portion is coaxially fitted to each of step-like
inner peripheral portions which are recessed on punched end
surfaces in both of the driven members.
4. A power switching apparatus according to claim 1, wherein the
switching means moves both of the cages in the axial direction
based on an electromagnetic force.
5. A power switching apparatus according to claim 2, wherein the
switching means moves both of the cages in the axial direction
based on an electromagnetic force.
6. A power switching apparatus according to claim 3, wherein the
switching means moves both of the cages in the axial direction
based on an electromagnetic force.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power switching apparatus which
is preferable for switching a two-wheel drive state and a
four-wheel drive state, in a vehicle.
2. Description of the Related Art
In power switching apparatuses for a vehicle, as described in
Japanese Patent Application Laid-Open No. 2001-80385 (JP-A), there
are structures having the following features. A differential
transmits rotation of a drive shaft to a wheel pair. A first rotary
member corresponds to an output member of the differential in a
side of one wheel, and a second rotary member is arranged to be
relatively rotatable to the first rotary member and which
integrally rotates with one wheel. A third rotary member integrally
rotates with a case of the differential rotating in correspondence
to the rotation of the drive shaft. A dog clutch can be switched
among a first position at which a connection between the first
rotary member and the second rotary member is cancelled, a second
position at which the first rotary member and the second rotary
member are connected, and a third position at which the first
rotary member, the second rotary member and the third member are
connected.
In the prior art, a two-wheel drive state in which rear wheels are
only driven may be established, during which time the dog clutch is
at the first position. A differential free state (a four-wheel
drive state capable of absorbing rotation difference between right
and left front wheels during a vehicle turning operation) in which
four wheels are driven is established when the dog clutch is at the
second position. A differential lock state (a direct-connection
four-wheel drive state capable of integrally rotating the right and
left front wheels so as to improve a traveling characteristics) in
which four wheels are driven may be established when the dog clutch
is at the third position.
In the conventional power switching apparatus, the differential
mechanism for switching the two-wheel drive state, the four-wheel
drive differential free state and the four-wheel drive differential
lock state involves installation of a bevel gear. Therefore, the
structure becomes complex and large in size.
Further, since the switching operation is executed by using the dog
clutch, it is necessary to align phases for engagement and
disengagement of a sleeve and a spline which constitute the dog
clutch.
SUMMARY OF THE INVENTION
An object of the present invention is to stably and easily switch
between a complete two-wheel drive state and a complete four-wheel
drive state based on a compact and simple structure. In this case,
the complete two-wheel drive state means a state in which only two
front wheels or only two rear wheels are driven. The complete
four-wheel drive state means a state in which the two front wheels
and the two rear wheels are driven, and the right and left wheels
are driven based on the integral rotation.
According to the present invention, there is disclosed a power
switching apparatus for switching a power transmitting state from a
drive member to right and left two driven members, comprising the
following structure.
A circumferential connection surface is provided in a drive member.
Circumferential connection surfaces are provided in both of the
driven members. The circumferential connection surface of the drive
member and the circumferential connection surfaces of the driven
members are coaxially arranged inside and outside.
An annular space forms a wedge-like gap in a peripheral direction
between the circumferential connection surface of the drive member
and the circumferential connection surfaces of both of the driven
members in a repeated manner.
Cages are respectively corresponding to both of the driven members,
the cages being received in the annular space.
A plurality of rolling elements are held at a plurality of
positions in a peripheral direction of each of the cages.
An energizing member brings each of the rolling elements into
contact with the circumferential connection surfaces in the drive
means and one of the driven members, and energizes each of the
rolling elements in a direction in which the rolling elements are
not in contact with the circumferential connection surfaces in the
drive member and another of the driven members.
A switching means moves each of the cages in an axial direction,
brings an end surface of each of the cages into frictional contact
with the drive member and another of the driven member so as to
rotate together therewith, and wedge connects the circumferential
connection surface of the drive member and each of the
circumferential connection surfaces in both of the driven members
according to an interposition of the rolling elements.
A spacer which is coaxially arranged with the driven members is
provided between both of the driven members, and both of the cages
are supported by an outer periphery of the spacer.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more fully understood from the
detailed description given below and from the accompanying drawings
which should not be taken to be a limitation on the invention, but
are for explanation and understanding only.
The drawings
FIG. 1 is a cross sectional view which shows a power switching
apparatus;
FIG. 2 is an enlarged view of a main portion in FIG. 1;
FIG. 3 is a cross sectional view along a line III--III in FIG. 2,
and shows a non-wedge connection state;
FIG. 4 is a cross sectional view along a line III--III in FIG. 2,
and shows a wedge connection state;
FIG. 5 is an exploded perspective view of the power switching
apparatus; and
FIG. 6 is an enlarged view of a main portion in FIG. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
According to the invention, a vehicle to which the present
invention is applied is structured such that a transmission is
connected to an output side of an engine. A drive shaft is
connected to an output side of the transmission. Right and left
rear wheel sets are connected to an end of the drive shaft in a
side of the rear wheels via a differential, and right and left
front wheel sets are connected to an end of the drive shaft in a
side of the front wheels via a power switching apparatus 10. In
this vehicle, an engine rotating force which is transmitted to the
differential of the rear wheels from the drive shaft is always
transmitted to the rear wheels, and a rotating force which is
transmitted to the power switching apparatus 10 in the side of the
front wheels from the drive shaft is transmitted to the right and
left front wheels according to a switching operation of the power
switching apparatus 10. When the power switching apparatus 10 is in
an off mode in which the power switching apparatus 10 does not
transmit the rotating force to the right and left front wheels, the
vehicle operates in a complete two-wheel drive state in which the
vehicle is driven only by two rear wheels. When the power switching
apparatus 10 is in an on mode in which the power switching
apparatus 10 transmits the rotating force to the right and left
front wheels, the vehicle operates in a complete four-wheel drive
state in which the vehicle is directly driven by two front wheels
and is driven by two rear wheels.
The power transmitting apparatus 10 is, as shown in FIG. 1 to FIG.
6, such that first to third housings 11A to 11C are integrally
connected by a bolt 10A. A pinion gear shaft 12 provided with a
pinion gear 12A is supported to the housing 11A via bearings 13A
and 13B. A yoke 14 is fixed to the pinion gear shaft 12 according
to a spline connection, and the drive shaft mentioned above is
connected to the yoke 14.
A drive member 15 is supported to the housing 11A and the housing
11B via bearings 16 and 17. The drive member 15 corresponds to an
assembled body, in which a ring gear shaft 18 which is provided
with a ring gear 18A, and a case 19, are integrally connected by a
bolt 20. The ring gear 18A is engaged with the pinion gear 12A.
Accordingly, the drive member 15 is always driven by a rotation of
the drive shaft.
Two left and right driven members 21 and 22 and a spacer 23 held
between the driven members 21 and 22 are arranged between end
surfaces which are opposed to each other on a center axis of the
ring gear shaft 18 and the case 19 constituting the drive member
15. A left front wheel set 24 is fixed to the driven member 21
through a spline connection, and a right front wheel set 25 is
fixed to the driven member 22 through a spline connection.
At this time, the drive member 15, both of the driven members 21
and 22 and the spacer 23 are coaxially arranged with each other. A
step-like outer peripheral portion 21A which is provided on an
outward end surface of the driven member 21 in a protruding manner
is coaxially fitted to a step-like inner diameter portion 18B which
is provided on a punched end surface of the ring gear shaft 18 in a
recess manner, so as to be capable of relatively rotating. The
outward end surface of the driven member 21 can be abutted against
the punched end surface of the ring gear shaft 18 in an axial
direction thereof. A step-like outer peripheral portion 22A which
is provided on an outward end surface of the driven member 22 in a
protruding manner is coaxially fitted to a step-like inner diameter
portion 19A which is provided on a punched end surface of the case
19 in a recess manner, so as to be capable of relatively rotating.
The outward end surface of the driven member 22 can be abutted
against the punched end surface of the case 19 in an axial
direction thereof. Further, step-like outer diameter portions 23A
and 23B which are respectively provided on both side end surfaces
of the spacer 23 in a protruding manner are coaxially fitted to
step-like inner peripheral portions 21B and 22B which are provided
on a punched end surface of the driven member 21 and the driven
member 22 in a recess manner, respectively. The respective side end
surfaces of the spacer 23 can be abutted against the respective
punched end surfaces of the driven member 21 and the driven member
22 in an axial direction thereof. Accordingly, both of the driven
members 21 and 22 and the spacer 23 are held in the drive member 15
(the ring gear shaft 18 and the case 19) in a state in which they
can relatively rotate. The drive member 15 (the ring gear shaft 18
and the case 19), both of the driven members 21 and 22 and the
spacer 23 are coaxially arranged in a state in which they are
coaxially fitted to each other.
Further, in the power switching apparatus 10, a circumferential
connection surface 30 which is provided on an inner diameter
surface of the case 19 constituting the drive member 15, and
circumferential connection surfaces 31 and 32 which are provided on
outer diameter surfaces of both of the driven members 21 and 22 are
coaxially arranged inside and outside, respectively, as shown in
FIGS. 2 and 3. The circumferential connection surface 30 of the
case 19 is formed in a polygonal shape. A wedge-like gap 33A is
formed in which both sides (a forward rotating direction and a
backward rotating direction) in a circumferential direction are
narrow, in an annular space 33 between the circumferential
connection surface 30 of the case 19 and the circumferential
connection surfaces 31 and 32 of both of the driven members 21 and
22, in a repeated manner.
Further, the power switching apparatus 10 receives cages 41 and 42
respectively corresponding to both of the driven members 21 and 22
in the annular gap 33 between the drive member 15 (the case 19) and
both of the driven members 21 and 22. The power switching apparatus
10 holds roller-like rolling elements 43 and 44 in pockets 41A and
42A which are provided at a plurality of positions in a peripheral
direction of the respective cages 41 and 42, thereby constituting a
roller clutch mechanism according to the following manner.
The power switching apparatus 10 is provided with annular grooves
43A and 44A in center portions of the respective rolling elements
43 and 44. A ring-like energizing member 45 which is provided in
the periphery of the driven member 21 is engaged with and attached
to the groove 43A of each of the rolling elements 43. The power
switching apparatus 10 is provided with a ring-like energizing
member 46 which is provided in the periphery of the driven member
22 and is engaged with and attached to the groove 44a of each of
the rolling bodies 44. The energizing member 45 is engaged with and
attached to the grooves 43A of all the rolling elements 43 which
are adjacent in the peripheral direction from the side of the
driven member 21, in a state in which one end bent portion is
engaged with the groove 43A of one rolling element 43. The
energizing member 45 energizes each of the rolling elements 43 in
such a manner as to be in contact with the maximum inner diameter
portion of the circumferential connection surface 30 in the case
19. The rolling element 43 is in non-contact with the
circumferential connection surface 31 of the driven member 21, and
is held in a neutral position. Accordingly, the energizing member
45 forms a racing state in which the drive member 15 (the case 19)
and the driven member 21 are not engaged (FIG. 3). The energizing
member 46 is engaged with and attached to the grooves 44A of all
the rolling elements 44 which are adjacent in the peripheral
direction from the side of the driven member 22, in a state in
which one end bent portion is engaged with the groove 44A of one
rolling element 44. The energizing member 46 energizes each of the
rolling elements 44, so as to be in contact with the maximum inner
diameter portion of the circumferential connection surface 30 in
the case 19. The rolling element 43 is in non-contact with the
circumferential connection surface 32 of the driven member 22, and
is held in a neutral position. Accordingly, the energizing member
46 forms a racing state in which the drive member 15 (the case 19)
and the driven member 22 are not engaged (the same as FIG. 3).
The power switching apparatus 10 has a switching means 50. The
switching means 50 switches modes from an off mode (a mode capable
of forming a complete two-wheel drive state in which the rear
wheels only are driven) to an on mode (a mode capable of forming a
complete four-wheel drive state in which the front and rear wheels
are driven). In the off mode, the drive member 15 and both of the
driven member 21 and 22 are placed in a disengaged state by the
energizing members 45 and 46 mentioned above so as to be capable of
racing. Power transmission from the drive member 15 to both of the
driven members 21 and 22 can thus be cancelled. In the on mode, the
drive member 15 and both of the driven members 21 and 22 are
engaged, and the power transmission from the drive member 15 to
both of the driven members 21 and 22 can be executed.
The switching means 50 can move the cages 41 and 42 slightly in an
axial direction with respect to flanges 21C and 22C of both of the
driven members 21 and 22, in a state of the followings; the inner
end surfaces of both of the cages 41 and 42 are placed back to back
with each other; inner peripheral portions 41B and 42B of the inner
end surfaces of both of the cages 41 and 42 are supported by an
outer peripheral guide surface 23C of the spacer 23, when receiving
both of the cages 41 and 42 in the annular gap 33 between the drive
member 15 and both of the driven members 21 and 22. In the on mode,
the switching means 50 slides and guides both of the cages 41 and
42 by the guide surface 23C of the spacer 23 so as to move them to
an outer side in an axial direction. This also brings the outer end
surfaces of the respective cages 41 and 42 into contact with the
opposing flanges 21C and 22C of the driven members 21 and 22 so as
to achieve friction contact. Then, the switching means 50 makes the
respective cages 41 and 42 capable of rotating together with the
respective driven members 21 and 22. In this state, when the drive
member 15 is rotated forward and a rotation phase difference is
further generated between the drive member 15 and the driven
members 21 and 22, the rolling elements 43 and 44 of the respective
cages 41 and 42 move relatively in a positive direction in a
peripheral direction of the circumferential connection surface 30
in the case 19. They wedge connect the circumferential connection
surface 30 of the case 19 to the circumferential connection
surfaces 31 and 32 of both of the driven members 21 and 22, and
integrally rotate the drive member 15 (the case 19) and the driven
members 21 and 22 in a forward rotating direction (FIG. 4). On the
other hand, when the drive member 15 is rotated backward and the
rotation phase difference is generated between the drive member 15
and the driven members 21 and 22, the rolling elements 43 and 44 of
the respective cages 41 and 42 move relatively in a reverse
direction in the peripheral direction of the circumferential
connection surface 30 in the case 19. They wedge connect the
circumferential connection surface 30 of the case 19 to the
circumferential connection surfaces 31 and 32 of both of the driven
members 21 and 22, and integrally rotate the drive member 15 (the
case 19) and the driven members 21 and 22 in a backward rotating
direction.
Accordingly, the switching means 50 moves both of the cages 41 and
42 in the axial direction via a ball cam mechanism as a result of
an electromagnetic force generated in the on mode. In particular,
an electromagnet 51 having an electromagnetic coil 51A built-in is
provided in the housing 11C. An armature plate 52 which is fixed to
a base end portion of a cam tube 54 fitted to an outer periphery of
the case 19 in such a manner as to be capable of moving in an axial
direction by a washer 53, is arranged in a front face of the
electromagnet 51. Thereby, the cam tube 54 can be moved based on an
electromagnetic force which is generated by an electric current
application to the electromagnet 51. Further, balls 56 are received
in through holes 55 which are provided at a plurality of positions
(for example, three positions) in the peripheral direction of the
case 19. Pressing cam surfaces 54A against the balls 56 are
provided in an inner periphery of a leading end portion of the cam
tube 54. Then the inclined surface driven cam surfaces 41C and 42C
are provided in outer peripheral portions of the inner end surfaces
in both of the cages 41 and 42.
Accordingly, in the on mode, the switching means 50 moves the cam
tube 54 as a result of the electromagnetic force of the
electromagnet 51, and presses the balls 56 to the inner side in the
diametrical direction by the pressing cam surfaces 54A of the cam
tube 54. Then, the balls 56 are pressed into the driven cam
surfaces 41C and 42C in both of the cages 41 and 42. As a result,
both of the cages 41 and 42 are respectively slid and guided by the
guide surface 23C of the spacer 23 so as to be moved in an outer
side in the axial direction, whereby the outer end surfaces of the
cages 41 and 42 can be respectively pressed against the flanges 21C
and 22C of the driven members 21 and 22.
The switching means 50 is controlled by a control apparatus. That
is, when vehicle speed detected by a vehicle speed sensor gets
around to a high vehicle speed state which is over a predetermined
fixed value, an electric current is applied to the electromagnet
51, and the mode is switched from the off mode mentioned above to
the on mode.
In this case, the switching means 50 can switch the mode from the
off mode to the on mode based on manual operation by a vehicle
driver.
Accordingly, the power switching apparatus 10 operates in the
following manner.
(A) Complete Two-wheel Drive State
In a state in which the electric current application to the
electromagnet 51 is turned off and the switching means 50 is set in
the off mode, when the wedge-connection between the drive member 15
and the left and right driven members 21 and 22 is cancelled, the
driving force to the left and right driven members 21 and 22 is not
transmitted. Thus, a complete two-wheel drive state is achieved.
The racing in the bevel gear or the like of the differential does
not take place, and fuel consumption is improved.
(B) Complete Four-wheel Drive State
In a state in which the electric current application to the
electromagnet 51 is turned on and the switching means 50 is set in
the on mode, when a rotation phase difference is generated between
the drive member 15 and the driven members 21 and 22 due to a
sudden acceleration of the engine rotating force or the like, the
drive member 15 and the left and right driven members 21 and 22 are
immediately wedge connected. As a result, driving force to the left
and right driven members 21 and 22 is transmitted, and a complete
four-wheel drive state is achieved. Since both of the left and
right driven members 21 and 22 are wedge connected to the drive
member 15, the rotating forces transmitted to the left and right
driven members 21 and 22 are uniform, and high speed straight
traveling stability is improved.
Further, since the connection state is maintained even during
engine braking or during sudden speed reduction, straight traveling
stability is maintained.
According to the present embodiment, the following effects can be
obtained.
(1) Since the power switching apparatus 10 has no differential gear
built-in, it is possible to make the structure compact and simple,
and to reduce weight.
(2) The switching means 50 moves the cages 41 and 42 in the axial
direction as a result of the electromagnetic force, and brings the
end surfaces of the cages 41 and 42 into frictional contact with
the flanges 21C and 22C of the driven members 21 and 22 so as to
rotate together therewith. The drive member 15 and the left and
right driven members 21 and 22 can be wedge connected to each other
according to an interposition of the rolling elements 43 and 44
immediately after the rotation phase difference is generated
between the driven members 21 and 22 and the drive member 15 (a
roller clutch mechanism). The wedge connection between the drive
member 15 and the driven members 21 and 22 can be easily and
lightly engaged and disengaged.
(3) It is possible to easily arrange two cages 41 and 42 on the
same axis so as to make it possible to stabilize the movement of
the cages 41 and 42 in the axial direction, by supporting both of
the cages 41 and 42 on the outer peripheral guide surface 23C of
the spacer 23 which is coaxially arranged on both of the driven
members 21 and 22. Accordingly, it is possible to further lightly
engage and disengage the wedge connection between the drive member
15 and the driven members 21 and 22.
(4) It is possible to easily assemble three elements comprising
both the driven members 21 and 22 and the spacer 23 on the same
axis by coaxially fitting the respective end portions of both of
the driven members 21 and 22 to both end portions of the spacer
23.
As heretofore explained, embodiments of the present invention have
been described in detail with reference to the drawings. However,
the specific configurations of the present invention are not
limited to the embodiments but those having a modification of the
design within the range of the present invention are also included
in the present invention. For example, the structure may be made
such that the circumferential connection surface of the drive
member and each of the circumferential connections of both of the
driven members are wedge connected according to an interposition of
the rolling elements. This may be caused by the followings; the
rolling elements in each of the cages may be held in contact with
the polygonal circumferential connection surface of the driven
member by the energizing member so as to energize in a direction in
which the rolling elements are not in contact with the
circumferential connection surface of the drive member; and the end
surface of the cage moved in the axial direction as a result of the
electromagnetic force, would be brought into frictional contact
with the drive member so as to rotate together therewith, when the
switching means is set to the on mode.
The switching means may move both of the cages in the axial
direction based on a centrifugal force in place of the
electromagnetic force. At this time, as the switching means, the
following structure may be employed. A ball abutment surface which
is angular in the axial direction of the cage is provided in an
inner diameter side of the cage. The ball is abutted against the
ball abutment surface of the cage, and the cage can be moved in the
axial direction based on the centrifugal force which is applied to
the ball.
As described above, according to the present invention, it is
possible to stably and easily switch between the complete two-wheel
drive state and the complete four-wheel drive state, based on a
compact and simple structure.
Although the invention has been illustrated and described with
respect to several exemplary embodiments thereof, it should be
understood by those skilled in the art that the foregoing and
various other changes, omissions and additions may be made to the
present invention without departing from the spirit and scope
thereof. Therefore, the present invention should not be understood
as limited to the specific embodiment set out above, but should be
understood to include all possible embodiments which can be
embodied within a scope encompassed and equivalents thereof with
respect to the features set out in the appended claims.
* * * * *